1. Field of the Invention
The present general inventive concept relates to an apparatus used with a digital broadcasting receiving apparatus, and a reception method thereof. More particularly, the present general inventive concept relates to a digital broadcasting receiving apparatus capable of coping with a situation that occurs when there are a plurality of physical channels corresponding to one selected virtual channel, and a reception method thereof.
2. Description of the Related Art
As the digital industry has developed, standardization of digital broadcasting is under way also in television (TV) broadcasting. A transmitting end in a digital system compresses and encodes an image or a voice, and multiplexes the image or the voice as a single data stream. A receiving end corrects an error generated in the received data stream, demultiplexes and decodes the image and the voice to output the image and the voice.
One of characteristics of the digital broadcasting and the digital TV (DTV) is multi-channelization. While an analog system enables transmission of only one program to one bandwidth, the digital system enables transmission of about four programs to the same bandwidth. Thus, the digital system guarantees multiple channels as the above since the digital system employs a moving picture experts group (MPEG)-2 technology which enables high density compression and decompression of image and voice. Therefore, by the digital system, high quality image and sound effects, as provided at a movie theater, is obtainable even at home.
The multi-channelizing of the digital broadcasting allows a user to select a broadcasting signal of diverse and clear image qualities. In general, the user selects a desired channel using a remote controller or a channel selecting means mounted to a receiving apparatus body. The recent receiving apparatus is provided with an auto channel searching function in which the channels are automatically set without requiring a user's direct selection of the broadcasting channel. The auto channel searching function skips channels where the broadcasting signal is not received or is rarely received, and automatically sets channels where the broadcasting signal is received.
However, a physical channel of the DTV has a drawback in that the user has to additionally be aware of channel numbers of the DTV. Accordingly, virtual channel is used to reduce the user's burden of recognizing a lot of channels, and utilizes existing channel numbers which are already well known to the audience. The virtual channels correspond to channels allotted to the respective analog broadcasting signals. For example, in Korea as of August, 200,3 the virtual channel numbers 9, 7, 13, 11, 6 and 8 are allocated respectively to broadcasting stations KBS1, KBS2, EBS, MBC, SBS (non-government broadcasting) and iTV.
According to domestic DTV broadcasting regulations, each broadcasting station employs different physical transport channels (PTC) for broadcasting. The PTC is divided by regional groups. By way of example, the PTC of MBC in Seoul, the capital of Korea, is 15 while the PTC of MBC in Cheongju, which is another city in Korea, is 20. However, in the domestic digital broadcasting, since local broadcasting stations are not equipped with conditions for producing digital contents by themselves, the local broadcasting stations usually retransmit the broadcasting signal of the main broadcasting station. Relay centers established in places also receive the broadcasting signal from the broadcasting stations, and retransmit the signal to the respectively allocated PTCs.
As described above, when one virtual channel is used in many different places, a plurality of broadcasting signals having the same virtual channel may be received in some places. Therefore, if the user selects the virtual channel of this kind of broadcasting signal, it becomes hard to determine the physical channel to be selected on the digital broadcasting receiving apparatus. As a result, solutions are required for when the signals are overlapped over a virtual channel.